Chap.XII.] means op dispersal. 145 



the small, is interesting; as plants with large seeds or 

 fruit which, as Alph. de CandoUe has shown, generally 

 have restricted ranges, could hardly be transported by 

 any other means. 



Seeds may be occasionally transported in another 

 manner. Drift timber is thrown up on most islands, 

 even on those in the naidst of the widest oceans; and 

 the natives of the coral-islands in the Pacific procure 

 stones for their tools, solely from the roots of drifted 

 trees, these stones being a valuable royal tax. I find 

 that when irregularly shaped stones are embedded in 

 the roots of trees, small parcels of earth are frequently 

 enclosed in their interstices and behind them, — so per- 

 fectly that not a particle could be washed away during 

 the longest transport: out of one small portion of earth 

 thus completely enclosed by the roots of an oak about 50 

 years old, three dicotyledonous plants germinated: I am 

 certain of the accuracy of this observation. Again, I 

 can show that the carcases of birds, when floating on the 

 sea, sometimes escape being immediately devoured: and 

 many kinds of seeds in the crops of floating birds long 

 retain their vitality: peas and vetches, for instance, are 

 killed by even a few days' immersion in sea-water; but 

 some taken out of the crop of a pigeon, which had floated 

 on artiflcial sea- water for 30 days, to my surprise nearly 

 all germinated. 



Living birds can hardly fail to be highly effective 

 agents in the transportation of seeds. I could give 

 many facts showing how frequently birds of many kinds 

 are blown by gales to vast distances across the ocean. 

 We may safely assume that under such circumstances 

 their rate of flight would often be 35 miles an hour; 

 and some authors have given a far higher estimate. I 



